Local track irregularity identification based on multi-sensor time-frequency features of high-speed railway bridge accelerations

Shortwave track diseases are generally reflected in the form of local track irregularity. Such diseases will greatly impact the train-track-bridge interaction (TTBI) dynamic system, seriously affecting train safety. Therefore, a method is proposed to detect and localize local track irregularities based on multis-sensor time-frequency features of high-speed railway bridge accelerations. Continuous wavelet transform (CWT) is used to analyze the multi-sensor accelerations of railway bridges. Moreover, time-frequency features based on the sum of wavelet coefficients are proposed, considering the influence of the distance from the measurement points to the local irregularity on the recognition accuracy. Then, the multi-domain features are utilized to recognize deteriorated railway locations. A simply-supported high-speed railway bridge traversed by a railway train is adopted as a numerical simulation. Comparative studies are conducted to investigate the influence of vehicle speeds and the location of local track irregularity on the algorithm. Numerical simulation results show that the proposed algorithm can detect and locate local track irregularity accurately and is robust to vehicle speeds

Chloride Ion Erosion of Pre-Stressed Concrete Bridges in Cold Regions

The erosion of chloride ions in concrete bridges will accelerate the corrosion of reinforcement, which is an important reason for the decline of bridge durability. The erosion process of chloride ion, especially deicing salt solution in cold regions, is complex and has many influencing factors. It is very important to use accurate and effective methods to analyze the chloride ion erosion process in concrete. In this study, the pre-stressed concrete bridge retired in the cold region was taken as the research object, and the specimens from the whole bridge are obtained by the method of core drilling sampling. The concentration of chloride ion was measured at different depths of the specimens. The process of chloride ion erosion was simulated in two-dimensional space through COMSOL multi-physical field simulation, and compared with the measured results. The simulation method proposed in this paper has good reliability and accuracy

Displacement filed calculation of large-scale structures using computer vision with physical constrains

Because of the advantages of easy deployment, low cost and non-contact, computer vision-based structural displacement acquisition technique has received wide attention and research in recent years. However, the displacement field acquisition of large-scale structures is a challenging topic due to the contradiction of camera field of view and resolution. This paper presents a large-scale structural displacement field calculation framework with integrated computer vision and physical constraints using only one camera. Firstly, the full-field image of the large-scale structure is obtained by processing the multi-view image using image stitching technique; secondly, the full-field image is meshed and the node displacements are calculated using an improved template matching method; and finally, the non-node displacements are described using shape functions considering physical constraints. The developed framework was validated using a scaled bridge model and evaluated by the proposed evaluation index for displacement field calculation accuracy. This paper can provide an effective way to obtain displacement fields of large-scale structures efficiently and cost-effectively

Effect of 17α-methyltestosterone (MT) on osmoregulatory responses and apoptosis in genetically improved farmed tilapia (GIFT), Oreochromis niloticus (L.)

361-368Androgenic compounds can affect osmoregulatory response and apoptosis in fish. In the present study, we exposed genetically improved farmed tilapia (GIFT) Oreochromis niloticus (L.) to 17α-methyltestosterone (MT, 0.5 and 5 mg/L) for 7, 14 and 21 days for understanding the phenomenon. The activities of Na+/K+ ATPase (NKA) and Ca2+/Mg2+ ATPase (CMA) were measured in the gill, kidney and intestine to evaluate the change in osmoregulation of GIFT, and genotoxicity was also detected. Results showed that organic NKA were significantly decreased in 5 mg/L MT exposure groups. The intestine NKA was significantly increased (0.5 mg/L MT). MT exposures increased the CMA of kidney and intestine (0.5 mg/L), together with gill CMA (5 mg/L MT). The results of genotoxicity assay showed gill atp1a1a and nkcc2 transcripts significantly increased, while intestine atp1a1a and fxyd7 transcripts revealed significant increases for MT exposure groups. Caspases proteins demonstrated significant increases at 7th and 21st day, and their transcripts were enhanced in 0.5 mg/L MT exposure groups. The results have evidently demonstrated that chronic exposure of MT could result in organic osmoregulatory response and hepatic apoptosis in GIFT O. niloticus

Effect of 17α-methyltestosterone (MT) on osmoregulatory responses and apoptosis in genetically improved farmed tilapia (GIFT), Oreochromis niloticus (L.)

Androgenic compounds can affect osmoregulatory response and apoptosis in fish. In the present study, we exposed genetically improved farmed tilapia (GIFT) Oreochromis niloticus (L.) to 17α-methyltestosterone (MT, 0.5 and 5 mg/L) for 7, 14 and 21 days for understanding the phenomenon. The activities of Na+/K+ ATPase (NKA) and Ca2+/Mg2+ ATPase (CMA) were measured in the gill, kidney and intestine to evaluate the change in osmoregulation of GIFT, and genotoxicity was also detected. Results showed that organic NKA were significantly decreased in 5 mg/L MT exposure groups. The intestine NKA was significantly increased (0.5 mg/L MT). MT exposures increased the CMA of kidney and intestine (0.5 mg/L), together with gill CMA (5 mg/L MT). The results of genotoxicity assay showed gill atp1a1a and nkcc2 transcripts significantly increased, while intestine atp1a1a and fxyd7 transcripts revealed significant increases for MT exposure groups. Caspases proteins demonstrated significant increases at 7th and 21st day, and their transcripts were enhanced in 0.5 mg/L MT exposure groups. The results have evidently demonstrated that chronic exposure of MT could result in organic osmoregulatory response and hepatic apoptosis in GIFT O. niloticus

Quantum Correlation in One-dimensional Extend Quantum Compass Model

We study the correlations in the one-dimensional extended quantum compass model in a transverse magnetic field. By exactly solving the Hamiltonian, we find that the quantum correlation of the ground state of one-dimensional quantum compass model is vanishing. We show that quantum discord can not only locate the quantum critical points, but also discern the orders of phase transitions. Furthermore, entanglement quantified by concurrence is also compared.Comment: 8 pages, 14 figures, to appear in Eur. Phys. J.

Fisher Concord: Efficiency of Quantum Measurement

By comparing measurement-induced classical Fisher information of parameterized quantum states with quantum Fisher information,we study the notion of Fisher concord (as abbreviation of the concord between the classical and the quantum Fisher information), which is an information-theoretic measure of quantum states and quantum measurements based on both classical and quantum Fisher information. Fisher concord is defined by multiplying the inverse square root of quantum Fisher information matrix to measurement-induced classical Fisher information matrix on both sides, and quantifies the relative accessibility of parameter information from quantum measurements (alternatively, the efficiency of quantum measurements in extracting parameter information). It reduces to the ratio of the classical Fisher information to quantum Fisher information in any single parameter scenario. In general, Fisher concord is a symmetric matrix which depends on both quantum states and quantum measurements. Some basic properties of Fisher concord are elucidated. The significance of Fisher concord in quantifying the interplay between classicality and quantumness in parameter estimation and in characterizing the ef- ficiency of quantum measurements are illustrated through several examples, and some information conservation relations in terms of Fisher concord are exhibited

From asymmetry to correlations

Symmetry, as well as the dual concept of asymmetry, are essential, powerful and ubiquitous in physics and nature. Motivated by the original Wigner-Yanase skew information and its extension by Dyson (Wigne

Understanding the Antecedents of Organic Food Purchases: The Important Roles of Beliefs, Subjective Norms, and Identity Expressiveness

China is expected to become an increasingly important market for global organic food producers. This study aims to obtain a new and deeper understanding of how various antecedents affect organic food purchase behavior. Here, a survey based on validated measures is designed, and a total of 1750 consumers are interviewed. In addition to traditionally held beliefs concerning organic food, three unique perspectives, i.e., that organic foods are “luxuries for the rich”, “upscale”, and the objects of “marketing hype”, are confirmed for the first time. Furthermore, the influence of subjective norms on purchase intention is verified to be completely mediated by purchase attitude, suggesting that up to now, the role of social norms may have been simplified, and even underestimated by marketing researchers. Additionally, for the first time, identity expressiveness is confirmed to play a minor but significant role in purchase intention. Perceived trustworthiness is also confirmed to be the important predictor of purchase intention. Finally, household income is not only the second most important predicator of purchase intention, but it is also the most important predictor of actual purchase. These findings will be valuable for marketing scholars and all stakeholders in the organic food industry, particularly international agribusinesses that are wishing to enter the Chinese market

Spatial Effect Analysis of Total Factor Productivity and Forestry Economic Growth

This paper takes 31 provinces in China from 2009 to 2018 as the research object. The three-stage data envelopment analysis (DEA) model was used to measure the total factor productivity of forestry, and the entropy method was used to measure the level of economic development and ecological construction. We used the global Moran index to explore the spatial correlation of forestry economic growth, and the local Moran index to explore the spatial agglomeration of forestry economic growth. On this basis, the spatial Durbin model was constructed to explore the spatial spillover effect between forestry total factor productivity and forestry economic growth. The conclusion is as follows: the total factor productivity of forestry in China is increasing continuously, and there are obvious spatial differences. Forestry economic growth has a significant spatial autocorrelation, and an overall upward trend. However, the spatial agglomeration effect was relatively weak and in the beginning stage of its formation. Total factor productivity of forestry has significant direct effect on the growth of forestry economy and forms an indirect spillover effect. Based on this, the countermeasures and suggestions to promote the benign and coordinated development of the forestry economy were put forward